Buruli ulcer’s mode of transmission is presently unknown, but in Victoria, Australia, endemic areas have been carefully mapped and patients are known to report single visits or defined exposures to these areas. From a retrospective review, Jason Trubiano and colleagues identified 23 patients with a single visit exposure to BU-endemic regions from a total of 408 diagnoses in Victoria over a decade and have estimated a likely incubation period of Mycobacterium ulcerans.

In this paper, Julien Lemaire and colleagues evaluate the impact of Leishmania major infection on deregulation of non-coding miRNAs, a class of important regulators of gene expression. Their results reveal the implication of several miRNAs on macrophage fate upon parasite infection through regulation of different pathways including cell death. These findings provide new insight for understanding mechanisms governing this miRNA deregulation by parasite infection and will help to provide clues for the development of control strategies for leishmaniasis.

It has been unknown how Leptospira cause disease and why different strains cause different severity of illness. In this study Jason Lehmann and colleagues attenuated a highly virulent strain of L. interrogans by culturing it in vitro over several months. Comparison of the whole genome sequence before and after the attenuation process revealed a small set of genes that were mutated, and therefore associated with virulence — a result that aids in the understanding of Leptospira evolution and pathogenesis.

The following new articles are publishing in PLOS Pathogens this week:

Chemicals are powerful tools in the control of malaria and other vector-borne diseases. Because temperature can affect the activity of chemicals used for vector control, Krijn P. Paaijmans and colleagues argue that candidate chemicals need to be evaluated under relevant climatic conditions. They also suggest that the range of temperatures currently recommended for development and field testing of new chemicals should be expanded.

Little is known about the early stages of primary pneumonic plague caused by pulmonary exposure to Yersinia pestis. Working with fully virulent Y. pestis in mice, William Goldman and colleagues now report that the bacteria primarily target pulmonary macrophages and neutrophils during the pre-inflammatory phase of disease, and that neutrophils are responsible for the severe necrotizing pneumonia during the pro-inflammatory disease phase.

Screening for substances that stimulate expression of interferon-inducible antiviral genes, Hélène Munier-Lehmann, Frédéric Tangy, Pierre-Olivier Vidalain and colleagues isolated compound DD246 from a chemical library and found that it targets the pyrimidine biosynthesis pathway. Their study establishes a link between inhibition of pyrimidine biosynthesis, amplification of antiviral gene expression, and inhibition of RNA virus infections.